In certain distance (shape) measurement devices, light is irradiated on the measurement object space, and the reflected light from the object is picked up by a CCD or another image pickup device. The picked up information is processed, and the distance to the object and the shape of the object are measured by the measurement device. As a scheme of such a measurement device, during the exposure time for 1 frame of the camera, slit light beams with an irradiated light quantity depending on the irradiating direction are irradiated on the measurement object space. Then, from the image picked up by the camera, the irradiating direction of the slit light beams is computed for each pixel from the variance of the exposure quantity by irradiation of the slit light beams.
Japanese Kokai Patent Publication Application No. 2002-131031 discloses a measurement device, based on the irradiating direction of the slit light beams computed for each pixel, the image pickup direction of each pixel, and the relationship between the position of the light source of the slit light beams and the position of the camera. The distance to the point or face of the object irradiated with the slit light beams is computed based on the principle of triangulation. From the distance information for all of the pixels of the camera computed in this way, the three-dimensional shape of the object in the measurement object space is measured.